Stocks in the United States moved sharply lower on Friday as President Donald Trump said he was ordering companies to look at how to close their operations in China and make more products at home.

Later in the day Trump said on Twitter that - starting on October 1 - the 25-percent tariffs on $250bn worth of Chinese goods will rise to 30 percent. Additionally, tariffs on the remaining $300bn in goods, due to begin on September 1, will now be set at 15 percent, rather than 10 percent.

The rhetorical strikes at Beijing came as trade tensions mounted, and as Trump faulted US Federal Reserve Chair Jerome Powell for not cutting interest rates aggressively enough.